docs: def _construct_from_json(self, rec):
          """ Construct this Dagobah instance from a JSON document. """
  
          self.delete()
  
          for required_key in ['dagobah_id', 'created_jobs']:
              setattr(self, required_key, rec[required_key])
  
          for job_json in rec.get('jobs', []):
              self._add_job_from_spec(job_json)
  
          self.commit(cascade=True)